Clinical Characteristics and Response to Long-Term Botulinum Toxin Type A Therapy in Patients with Cervical Dystonia at a Neurology Clinic

Abstract

Introduction: To determine the demographic and clinical characteristics and response to botulinum toxin type A (BoNT-A) therapy in patients with cervical dystonia (CD).

Method: A retrospective analysis of the detailed medical records of the patients with CD, followed up at our Botulinum Toxin Outpatient Clinic from 1998 to 2012, was performed. The treatment data were compared between the patients with primary CD and those with secondary CD; between patients receiving BoNT-A treatment for more than 5 years and less than five years, and between first applications and last applications.

Results: Fifty-seven patients (56.15% women) with CD were included in this study. The mean age was 41.01±13.42 years, the mean age at symptom onset was 32.93±15.45 years, and the mean dystonia duration was 8.10±8.5 years. The interval between onset of symptom and first BoNT-A treatment was 5.94±9.06 years, the duration of BoNT-A treatment was 36.13±29.17 months, and the number of applications was 8.48±6.23 in 45 patients with CD who were under treatment with BoNT-A for more than 1 year and had received at least three injections before. There was no difference between the patients with primary and secondary CD in terms of treatment results. The injection interval of the patients receiving BoNT-A treatment for more than 5 years and less than 5 years was 18.37±5.10 and 14.43±2.36 weeks, respectively (p=.001). There were no differences in the other treatment values. The mean doses were 559.00±147.60 vs. 681.66±188.09 units (p=.0001), the durations of improvement were 11.82±2.71 vs. 13.00±4.00 weeks (p=.014), the response scores were 2.71±.3 vs. 3.02±.5 (p=.002), the response ratings were 64.66%±16.18 vs. 71.22%±17.29 (p=.001), and the numbers of muscles applied were 3.15±1.16 vs. 3.51±0.99 (p=.012) in the first and last applications, respectively.

Conclusion: There were no differences between the response of the patients with primary and secondary CD. Our results showed a statistically significant increase in the mean dose of BoNT-A, the response rating, the number of muscles applied, the duration of improvement, and the injection interval over time.

Keywords: Cervical dystonia; botulinum toxin; clinical characteristics; clinical findings; demographic characteristics.